diff --git a/lib/Cake/Model/Datasource/DboSource.php b/lib/Cake/Model/Datasource/DboSource.php
index ea1c7dbca02..ef4bab7e743 100644
--- a/lib/Cake/Model/Datasource/DboSource.php
+++ b/lib/Cake/Model/Datasource/DboSource.php
@@ -2984,7 +2984,7 @@ public function createSchema($schema, $tableName = null) {
 						$tableParameters = array_merge($tableParameters, $this->buildTableParameters($col, $table));
 					}
 				}
-				if (empty($indexes) && !empty($primary)) {
+				if (!isset($columns['indexes']['PRIMARY']) && !empty($primary)) {
 					$col = array('PRIMARY' => array('column' => $primary, 'unique' => 1));
 					$indexes = array_merge($indexes, $this->buildIndex($col, $table));
 				}
diff --git a/lib/Cake/Test/Case/Model/Datasource/Database/MysqlTest.php b/lib/Cake/Test/Case/Model/Datasource/Database/MysqlTest.php
index f14bf611682..4f3baa0bdf2 100644
--- a/lib/Cake/Test/Case/Model/Datasource/Database/MysqlTest.php
+++ b/lib/Cake/Test/Case/Model/Datasource/Database/MysqlTest.php
@@ -877,6 +877,52 @@ public function testTwoColumnsWithPrimaryKey() {
 		$this->assertContains('`user_id` int(11) NOT NULL,', $result);
 	}
 
+/**
+ * Test that the primary flag is handled correctly.
+ *
+ * @return void
+ */
+	public function testCreateSchemaAutoPrimaryKey() {
+		$schema = new CakeSchema();
+		$schema->tables = array(
+			'no_indexes' => array(
+				'id' => array('type' => 'integer', 'null' => false, 'key' => 'primary'),
+				'data' => array('type' => 'integer', 'null' => false),
+				'indexes' => array(),
+			)
+		);
+		$result = $this->Dbo->createSchema($schema, 'no_indexes');
+		$this->assertContains('PRIMARY KEY  (`id`)', $result);
+		$this->assertNotContains('UNIQUE KEY', $result);
+
+		$schema->tables = array(
+			'primary_index' => array(
+				'id' => array('type' => 'integer', 'null' => false),
+				'data' => array('type' => 'integer', 'null' => false),
+				'indexes' => array(
+					'PRIMARY' => array('column' => 'id', 'unique' => 1),
+					'some_index' => array('column' => 'data', 'unique' => 1)
+				),
+			)
+		);
+		$result = $this->Dbo->createSchema($schema, 'primary_index');
+		$this->assertContains('PRIMARY KEY  (`id`)', $result);
+		$this->assertContains('UNIQUE KEY `some_index` (`data`)', $result);
+
+		$schema->tables = array(
+			'primary_flag_has_index' => array(
+				'id' => array('type' => 'integer', 'null' => false, 'key' => 'primary'),
+				'data' => array('type' => 'integer', 'null' => false),
+				'indexes' => array (
+					'some_index' => array('column' => 'data', 'unique' => 1)
+				),
+			)
+		);
+		$result = $this->Dbo->createSchema($schema, 'primary_flag_has_index');
+		$this->assertContains('PRIMARY KEY  (`id`)', $result);
+		$this->assertContains('UNIQUE KEY `some_index` (`data`)', $result);
+	}
+
 /**
  * Tests that listSources method sends the correct query and parses the result accordingly
  * @return void